No group has claimed responsibility for Tuesday’s attack, which came hours after small blasts went off near a couple of schools in Jalalabad city, the provincial capital of Nangarhar near the border with Pakistan and the scene of deadly strikes by the Islamic State in recent months.

A delegation from Kabul is heading to the province to probe the attack with a focus on its motive and if there is a connection to the local police commander Bilal Shah, a provincial official said by phone on condition of anonymity because of the sensitivity of the situation.

The protests involved hundreds of people and the bomber blew himself up among the crowd, which had blocked the main highway that links Kabul with Pakistan.

They wanted the dismissal and arrest of Shah, who is accused of severe abuses, including torture, abductions and even killings.

Shah was briefly arrested recently over allegations from locals, but was later freed.

“He was free when the blast took place, but has been jailed since. He will be referred to judicial organs and it has become a serious issue that is being looked at by the delegation from Kabul,” the official said.

Relatives and family members of Tuesday’s victims have continued blocking the highway, according to local witnesses.

The attack comes amid surge of strikes by the Islamic State and Taliban insurgents elsewhere in the country since last week in which more than 200 people have been killed.